Sealed package and method of forming same

ABSTRACT

Various embodiments of a sealed package and a method of forming such package are disclosed. The package can include a non-conductive substrate that includes a cavity disposed in a first major surface. A cover layer can be disposed over the cavity and attached to the first major surface of the non-conductive substrate to form a sealed enclosure. The sealed package can also include a feedthrough that includes a via between a recessed surface of the cavity and a second major surface of the substrate, and a conductive material disposed in the via. An external contact can be disposed over the via on the second major surface of the non-conductive substrate, where the external contact is electrically connected to the conductive material disposed in the via. The sealed package can also include an electronic device disposed within the sealed enclosure that is electrically connected to the external contact.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Continuation of U.S. patent application Ser. No.16/580,657, filed Sep. 24, 2019, which is a Continuation of U.S. patentapplication Ser. No. 16/158,801, now U.S. Pat. No. 10,420,509, filedOct. 12, 2018, which is a Continuation of U.S. patent application Ser.No. 15/359,974, now U.S. Pat. No. 10,098,589, filed Nov. 23, 2016, whichclaims the benefit of U.S. Provisional Patent Application No.62/270,119, filed Dec. 21, 2015, the entire content of each of which isincorporated by reference in its entirety.

BACKGROUND

Various systems require electrical coupling between electrical devicesdisposed within a hermetically sealed enclosure and external devices.Oftentimes, such electrical coupling needs to withstand variousenvironmental factors such that a conductive pathway or pathways fromthe external surface to within the enclosure remains stable. Forexample, implantable medical devices (IMDs), e.g., cardiac pacemakers,defibrillators, neurostimulators and drug pumps, which includeelectronic circuitry and battery elements, require an enclosure orhousing to contain and hermetically seal these elements within a body ofa patient. Many of these IMDs include one or more electrical feedthroughassemblies to provide electrical connection between the elementscontained within the housing and components of the IMD external to thehousing, for example, sensors and/or electrodes and/or lead wiresmounted on an exterior surface of the housing, or electrical contactshoused within a connector header, which is mounted on the housing toprovide coupling for one or more implantable leads, which typicallycarry one or more electrodes and/or one or more other types ofphysiological sensors. A physiological sensor, for example a pressuresensor, incorporated within a body of a lead may also require ahermetically sealed housing to contain electronic circuitry of thesensor and an electrical feedthrough assembly to provide an electricalconnection between one or more lead wires, which extend within theimplantable lead body, and the contained circuitry.

A feedthrough assembly typically includes one or more feedthrough pinsthat extend from an interior to an exterior of the housing through aferrule. Each feedthrough pin is electrically isolated from the ferrule,and, for multipolar assemblies, from one another, by an insulatorelement, e.g., glass or ceramic, that is mounted within the ferrule andsurrounds the feedthrough pin(s). Glass insulators are typically sealeddirectly to the pin(s) and to the ferrule, e.g., by heating the assemblyto a temperature at which the glass wets the pin(s) and ferrule, whileceramic insulators are typically sealed to the pin(s) and to the ferruleby a braze joint. High temperatures are typically required to joincorrosion-resistant conductive materials with corrosion-resistantinsulative materials.

SUMMARY

In general, the present disclosure provides various embodiments of asealed package and a method of forming such package. In one or moreembodiments, the sealed package can be a hermetically-sealed package.The sealed package can include a non-conductive substrate that includesa cavity disposed in a first major surface. A cover layer can bedisposed over the cavity and attached to the first major surface of thenon-conductive substrate to form a sealed enclosure. The sealed packagecan also include a feedthrough that includes a via between a recessedsurface of the cavity and a second major surface of the substrate, and aconductive material disposed in the via. An external contact can bedisposed over the via on the second major surface of the non-conductivesubstrate, where the external contact is electrically connected to theconductive material disposed in the via. In one or more embodiments, theexternal contact can be hermetically sealed to the second major surfaceof the non-conductive substrate using any suitable technique orcombination of techniques, e.g., a laser bond that at least partiallysurrounds the via can be formed between the external contact and thesecond major surface of the non-conductive substrate. In one or moreembodiments, the sealed package can include an electronic devicedisposed within the sealed enclosure. The electronic device can includea device contact that is electrically connected to the conductivematerial disposed in the via such that the electronic device iselectrically connected to the external contact.

In one aspect, the present disclosure provides a hermetically-sealedpackage that includes a non-conductive substrate including a first majorsurface, a second major surface, and a cavity disposed in the firstmajor surface. The cavity includes a recessed surface. The package alsoincludes a cover layer disposed over the cavity and attached to thefirst major surface of the non-conductive substrate to form ahermetically-sealed enclosure, and a feedthrough. The feedthroughincludes a via between the recessed surface of the cavity and the secondmajor surface of the substrate; a conductive material disposed in thevia; and an external contact disposed over the via on the second majorsurface of the non-conductive substrate. The external contact iselectrically connected to the conductive material disposed in the via,and the external contact is hermetically sealed to the second majorsurface of the non-conductive substrate by a laser bond surrounding thevia. The package also includes an electronic device disposed within thehermetically-sealed enclosure, where the electronic device includes adevice contact that is electrically connected to the conductive materialdisposed in the via such that the electronic device is electricallyconnected to the external contact.

In another aspect, the present disclosure provides a method of forming ahermetically-sealed package. The method includes forming a cavity in afirst major surface of a non-conductive substrate; forming a via betweena recessed surface of the cavity and a second major surface of thenon-conductive substrate; and forming an external contact over the viaon the second major surface of the non-conductive substrate. The methodfurther includes disposing conductive material in the via such that theexternal contact is electrically connected to the conductive material inthe via; disposing an electronic device at least partially within thecavity such that a device contact of the electronic device iselectrically connected to the conductive material in the via; disposinga cover layer over the cavity; and attaching the cover layer to thefirst major surface of the non-conductive substrate to form ahermetically-sealed enclosure. The electronic device is disposed withinthe hermetically-sealed enclosure.

In another aspect, the present disclosure provides a hermetically-sealedpackage that includes a non-conductive substrate including a first majorsurface, a second major surface, and a cavity disposed in the firstmajor surface. The cavity includes a recessed surface. The packagefurther includes an internal contact disposed on the recessed surface ofthe cavity; an electronic device including a device contact electricallyconnected to the internal contact; and a cover layer disposed over thecavity and attached to the first major surface of the non-conductivesubstrate to form a hermetically-sealed enclosure. The electronic deviceis disposed within the hermetically-sealed enclosure.

All headings provided herein are for the convenience of the reader andshould not be used to limit the meaning of any text that follows theheading, unless so specified.

The terms “comprises” and variations thereof do not have a limitingmeaning where these terms appear in the description and claims. Suchterms will be understood to imply the inclusion of a stated step orelement or group of steps or elements but not the exclusion of any otherstep or element or group of steps or elements.

In this application, terms such as “a,” “an,” and “the” are not intendedto refer to only a singular entity, but include the general class ofwhich a specific example may be used for illustration. The terms “a,”“an,” and “the” are used interchangeably with the term “at least one.”The phrases “at least one of” and “comprises at least one of” followedby a list refers to any one of the items in the list and any combinationof two or more items in the list.

The phrases “at least one of” and “comprises at least one of” followedby a list refers to any one of the items in the list and any combinationof two or more items in the list.

As used herein, the term “or” is generally employed in its usual senseincluding “and/or” unless the content clearly dictates otherwise.

The term “and/or” means one or all of the listed elements or acombination of any two or more of the listed elements.

As used herein in connection with a measured quantity, the term “about”refers to that variation in the measured quantity as would be expectedby the skilled artisan making the measurement and exercising a level ofcare commensurate with the objective of the measurement and theprecision of the measuring equipment used. Herein, “up to” a number(e.g., up to 50) includes the number (e.g., 50).

Also herein, the recitations of numerical ranges by endpoints includeall numbers subsumed within that range as well as the endpoints (e.g., 1to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.).

These and other aspects of the present disclosure will be apparent fromthe detailed description below. In no event, however, should the abovesummaries be construed as limitations on the claimed subject matter,which subject matter is defined solely by the attached claims, as may beamended during prosecution.

BRIEF DESCRIPTION OF THE DRAWINGS

Throughout the specification, reference is made to the appendeddrawings, where like reference numerals designate like elements, andwherein:

FIG. 1 is a schematic cross-section view of one embodiment of a sealedpackage.

FIG. 2 is a schematic plan view of the sealed package of FIG. 1.

FIG. 3 is a schematic plan view of a feedthrough of the sealed packageof FIG. 1.

FIG. 4 is a schematic cross-section view of a portion of the sealedpackage of FIG. 1.

FIG. 5 is a schematic plan view of a feedthrough of the sealed packageof FIG. 1.

FIG. 6 is a schematic cross-section view of another embodiment of asealed package.

FIG. 7 is a schematic plan view of another embodiment of a sealedpackage.

FIGS. 8A, 8B, 8C, 8D, 8E, 8F, 8G, 8H and 8I are schematic cross-sectionviews of a method of forming a sealed package.

FIG. 9 is a schematic side view of one embodiment of an implantablemedical device system.

FIG. 10 is a schematic cross-section view of the implantable medicaldevice of the system of FIG. 9.

FIG. 11 is a schematic cross-section view of a lead that includes thesealed package of FIG. 1.

FIG. 12 is a schematic cross-section view of another embodiment of asealed package.

FIGS. 13A, 13B, 13C, 13D, 13E, 13F, 13G and 13H are schematiccross-section views of another method of forming a sealed package.

DETAILED DESCRIPTION

In general, the present disclosure provides various embodiments of asealed package and a method of forming such package. In one or moreembodiments, the sealed package can be a hermetically-sealed package.The sealed package can include a non-conductive substrate that includesa cavity disposed in a first major surface. A cover layer can bedisposed over the cavity and attached to the first major surface of thenon-conductive substrate to form a sealed enclosure. The sealed packagecan also include a feedthrough that includes a via between a recessedsurface of the cavity and a second major surface of the substrate, and aconductive material disposed in the via. An external contact can bedisposed over the via on the second major surface of the non-conductivesubstrate, where the external contact is electrically connected to theconductive material disposed in the via. In one or more embodiments, theexternal contact can be hermetically sealed to the second major surfaceof the non-conductive substrate using any suitable technique orcombination of techniques, e.g., a laser bond that at least partiallysurrounds the via can be formed between the external contact and thesecond major surface of the non-conductive substrate. In one or moreembodiments, the sealed package can include an electronic devicedisposed within the sealed enclosure. The electronic device can includea device contact that is electrically connected to the conductivematerial disposed in the via such that the electronic device iselectrically connected to the external contact.

In one or more embodiments, the feedthrough can be formed through thesubstrate using low temperature techniques that do not require the useof ferrules, glasses, or brazing materials. Further, in one or moreembodiments, the feedthrough can be formed without creating unacceptablestresses in the materials used to form the feedthrough that can becaused by the use of high temperature bonding techniques. Further, inone or more embodiments, the external contact of the feedthrough and anoptional internal contact electrically coupled to the via can be ofsufficient size and thickness to enable laser, resistance, or otherwelding and joining techniques to be utilized to electrically coupleconductors and/or electronic devices to the contacts. In addition, inone or more embodiments, the disclosed low temperature processingtechniques can also allow for internal metallization such as Ti/Ni/Audirectly on a non-conductive substrate. This can, in one or moreembodiments, facilitate the disposition of various electronic devicesdirectly onto the substrate, e.g., integrated circuits, or discretecircuit components such as filtering capacitors, diodes, resistors,etc., as is further described herein.

FIGS. 1-5 are various schematic views of one embodiment of a sealedpackage 10. The package 10 includes a substrate 12 that has a firstmajor surface 14 and a second major surface 16. Substrate 12 alsoincludes a cavity 18 disposed in the first major surface 14. The cavity18 includes a recessed surface 19. The package 10 also includes a coverlayer 40 disposed over the cavity 18 and attached to the first majorsurface 14 of the substrate 12 to form a sealed enclosure 42. Thepackage 10 can also include a feedthrough 20 that includes a via 22between the recessed surface 19 of the cavity 18 and the second majorsurface 16 of the substrate. The feedthrough 20 can also includeconductive material 24 disposed in the via 22, and an external contact26 disposed over the via on the second major surface 16 of the substrate12. The external contact 26 can be electrically connected to theconductive material 24 disposed in the via 22. In one or moreembodiments, the external contact 26 can be sealed to the second majorsurface 16 of the substrate 12 using any suitable technique orcombination of techniques. In one or more embodiments, the externalcontact 26 can be hermetically sealed to the second major surface 16 ofthe substrate 12. Although depicted as including five feedthroughs 20,the package 10 can include any suitable number of feedthroughs, e.g., 1,2, 3, 4, 5, 10, 20, or more feedthroughs. Each feedthrough 20 can besubstantially identical in construction. In one or more embodiments, oneor more feedthroughs 20 can have characteristics that are different fromone or more additional feedthroughs. The feedthrough 20 can provide anelectrical pathway between the second major surface 16 and the enclosure42 of the package 10.

In one or more embodiments, the package 10 can also include anelectronic device 30 disposed within the enclosure 42. Electronic device30 can include one or more device contacts 32 that are electricallyconnected to the conductive material 24 in the via 22 such that theelectronic device is electrically connected to the external contact 26.

The substrate 12 can include any suitable material or combination ofmaterials. In one or more embodiments, the substrate 12 can be anon-conductive or insulative substrate such that external electrode 26and any conductors or other devices disposed on the substrate can beelectrically isolated if desired. In one or more embodiments, thesubstrate 12 can include at least one of glass, quartz, silica,sapphire, silicon carbide, diamond, synthetic diamond, and galliumnitride, or alloys or combinations (including clad structures,laminates, etc.) thereof.

Further, in one or more embodiments, the substrate 12 can besubstantially transparent at a desired wavelength or range ofwavelengths. As used herein, the phrase “substantially transparent” asit pertains to the substrate 12 means that the substrate meets at leastone or both of the following minimal energy absorption criteria: (1) theenergy transmitted through the substantially transparent substratematerial is sufficient to activate the bonding process at the interfacevia absorption by the opaque material (e.g., interface of substrate 12and external contact 26), and (2) any energy absorbed by the transparentmaterial will not be sufficient to melt, distort, or otherwise affectthe bulk of the transparent material that is away from the bondingregion. In other words, the laser bonding techniques described hereinwill preferentially heat only the second major surface 16 (or an outerlayer at the surface 16 of the substrate 12) over the inner bulk of thesubstrate 12 to create an enhanced bond, such as bond 48. Such a bondmay exhibit a relatively greater strength than the bulk strength of thesubstrate 12. Any suitable wavelength of light can be utilized providedthat the substrate 12 will transmit a given percentage of the light thatis directed at the substrate 12 to preferentially heat only the outersurface or outer layer instead of the inner bulk to create the enhancedbond. In one or more embodiments, the light is directed at substrate 12though the first major surface 14 or recessed surface 19 towards thesecond major surface 16 (or the outer layer at the second majorsurface). In accordance with the foregoing, a substrate that issubstantially transparent in one exemplary embodiment will transmit atleast 40% of light that is directed at the substrate for a selectedwavelength or range of wavelengths, assuming no reflection at theair-substrate boundaries. In accordance with the forgoing, it may bedesirable to select a substrate that is substantially transmissive tolight having a wavelength in a range of 10 nm to 30 μm in one or moreexemplary embodiments. In one or more embodiments, a substrate that issubstantially transparent may be selected that is transmissive to lightof any desired wavelength. Therefore, a substantially transparentsubstrate 12 will allow a sufficient amount of light having apredetermined magnitude to be transmitted through the inner bulk of thesubstrate to the second major surface 16 to create the bond 48. In oneor more embodiments, the substrate 12 can be substantially transmissiveto at least one of UV light, visible light, and IR light. The light canbe provided by a laser that has any suitable wavelength or range ofwavelengths and any suitable pulse width.

The substrate 12 can include any suitable shape or combination of shapesand any suitable dimensions, e.g., thicknesses. Further, the substrate12 can be a single unitary substrate or multiple substrates joinedtogether.

The cavity 18 disposed in the first major surface 14 of the substrate 12can take any suitable shape or combination of shapes and have anysuitable dimensions. Further, the cavity 18 can be formed in the firstmajor surface 14 of the substrate 12 using any suitable technique orcombination of techniques, e.g., etching, ablation, laser-assistedetching, and combinations thereof. The recessed surface 19 of the cavity18 can take any suitable shape or combination of shapes. In one or moreembodiments, the cavity 18 can be provided by disposing a frame betweena substrate that does not include a cavity formed therein and the coverlayer 40.

The cover layer 40 can include any suitable material or combination ofmaterials. In one or more embodiments, the cover layer 40 can includeone or more conductive materials, e.g., copper, silver, aluminum,chromium, nickel, gold, composites (e.g., silver-filled epoxies), andalloys or combinations (including clad structures, laminates, etc.)thereof. In one or more embodiments, the cover layer 40 can include ametal foil, e.g., a titanium foil. The metal foil can have any suitablethickness. In one or more embodiments, the cover layer 40 can includeone or more non-conductive materials, e.g., glass, quartz, silica,sapphire, silicon carbide, diamond, and gallium nitride, andcombinations thereof.

The cover layer 40 can take any suitable shape or combination of shapes.As illustrated in FIG. 1, the cover layer 40 is substantially planar. Inone or more embodiments, the cover layer 40 can include a recess that isat least partially aligned with the cavity 18 of the substrate 12 toform the enclosure 42 of the package 10.

The cover layer 40 can be attached to the substrate 12 using anysuitable technique or combination of techniques. For example, an innersurface 44 of the cover layer 40 can be sealed to the first majorsurface 14 of the substrate 12 by the bond 48 (FIG. 2) that at leastpartially surrounds the cavity 18. In one or more embodiments, the bond48 completely surrounds the cavity 18. Any suitable technique orcombination techniques can be utilized to form this bond 48, e.g., thesame techniques described herein for attaching the external contact 26.For example, the bond 48 can be formed using a laser to provide a laserbond. By surrounding the cavity 18 with the bond 48 that seals the coverlayer 14 to the first major surface 14 of the substrate 12, theelectronic device 30 and any other components disposed within theenclosure 42 can be protected from the external environment. In one ormore embodiments, this bond 48 can hermetically seal the cover layer 40to the first major surface 14 of the substrate 12. The bond 48 formedbetween the cover layer 40 and the first major surface 14 of thesubstrate 12 can take any suitable shape or combination of shapes.Further, this bond 48 can be a continuous bond or include multiplebonds, e.g., point bonds. In one or more embodiments, the bond 48 can bea bond line that forms a closed shape surrounding the cavity 18. As usedherein, the term “closed shape” means that the shape is entirelyenclosed such that its perimeter is unbroken and continuous.

In one or more embodiments, the bond 48 can be a bond region thatsurrounds the cavity 18. The bonded region can take any suitable shapeor combination of shapes. In one or more embodiments, the bond 48 caninclude two or more shapes with one shape circumscribing the secondshape. For example, the bond 48 can include two or more concentricelliptical bond lines or rings. In such embodiments, the two or moreshapes may be isolated so that the shapes do not intersect or overlap.In one or more embodiments, the two or more shapes may intersect oroverlap along any suitable portion or portions of the shapes. In one ormore embodiments, the bond 48 can include two or more bond lines thattogether surround the cavity 18. For example, the bond 48 can include aseries of parallel lines that are intersected by two or more lines thatare non-parallel to the series of parallel lines.

In one or more embodiments, the bond 48 can include an interfacial layerbetween the inner surface 44 of the cover layer 40 and the first majorsurface 14 of substrate 12. This interfacial layer can have any suitablethickness in a direction normal to the first major surface 14 of thesubstrate 12. In one or more embodiments, the interfacial layer has athickness in a direction normal to the first major surface 14 of thesubstrate 12 of no greater than 50 nm, 100 nm, 150 nm, 200 nm, nogreater than 1000 nm, etc.

As mentioned herein, the package 10 can include one or more feedthroughs20 to provide an electrical pathway between the second major surface 16of the substrate 12 and the enclosure 42. Although not shown, in one ormore embodiments, one or more feedthroughs 20 can also be disposed inthe cover layer 40 to provide an electrical pathway between an outersurface 46 of the cover layer and the enclosure 42. Further, in one ormore embodiments, one or more feedthroughs 20 can also be formed betweenthe enclosure 42 and an end surface 13 of the substrate 12 (also notshown).

The feedthrough 20 can include the via 22 between the second majorsurface 16 of the substrate 12 and the recessed surface 19 of the cavity18. The via 22 can be any suitable size and take any suitable shape. Thesize and shape of the via 22 can be predicated on the thickness of thesubstrate 12 and the techniques utilized to provide the conductivematerial that forms the electrical pathway between the second majorsurface 16 and the recessed surface 19 of the substrate 12. Exemplaryshapes for the via 22 may include parallel surface walls and taperedsurface walls. In one or more exemplary embodiments where the substrate12 has a thickness of approximately 100 to 500 μm, the via 22 can havean opening at the second major surface 16 of the substrate that is nogreater than 500 μm, that is no greater than 250 μm, no greater than 100μm, no greater than 80 μm, no greater than 50 μm, or no greater than 10μm. In one or more example embodiments where the substrate 12 has athickness of approximately 100 to 500 μm, the via 22 can also have anopening at the recessed surface 19 of the substrate 12 that has adiameter of no greater than 500 μm, no greater than 250 μm, no greaterthan 100 μm, no greater than 80 μm, no greater than 50 μm, or no greaterthan 10 μm. Of course, the diameter of the via 22 could be larger (orsmaller) than the illustrated examples based on the substrate thicknessand/or the techniques utilized to provide the conductive material thatforms the electrical pathway. Any suitable technique or combination oftechniques can be utilized to form the via 22, e.g., drilling, chemicaletching, laser etching, etc.

The feedthrough 20 can also include conductive material 24 disposed inthe via 22 to provide a conductive pathway between the second majorsurface 16 and the recessed surface 19 of substrate 12. The conductivematerial 24 can include any suitable conductive material or combinationof conductive materials, e.g., copper, titanium, aluminum, chromium,nickel, gold, composites (e.g., silver-filled epoxies), and combinationsthereof. The conductive material 24 can be disposed in the via 22 usingany suitable technique or combination of techniques to provide aconductive pathway between the external contact 26 to one or moredevices or contacts disposed within the sealed enclosure 42. In one ormore embodiments, the conductive material 24 can be disposed in the via22 such that it substantially fills the via. In one or more embodiments,the conductive material 24 can be disposed in the via 22 along sidewallsof the via and the opening of the via at the second major surface 16.

As mentioned herein, the feedthrough 20 includes the external contact26. In one or more embodiments, the external contact 26 can be adaptedto electrically connect the feedthrough 20 to a conductor or a contactof a device, e.g., the device contact 32 of the electronic device 30.Such conductors and contacts can be electrically connected to theexternal contact 26 using any suitable technique or combination oftechniques, e.g., soldering, physical contact, welding, etc. Theexternal contact 26 can include any suitable conductive material orcombination of conductive materials, e.g., copper, silver, titanium,niobium, zirconium, tantalum, stainless steel, platinum, iridium, oralloys or combinations (including clad structures, laminates, etc.)thereof. In one or more embodiments, the external contact 26 can includetwo or more materials, e.g., bi-metals, clad structures, or laminates,etc.

The external contact 26 can take any suitable shape or combination ofshapes. In one or more embodiments, the external contact 26 can take acircular shape in a plane parallel to the second major surface 16 of thesubstrate 12. In one or more embodiments, the external contact 26 cantake a rectangular shape in the plane parallel to the second majorsurface 16 of the substrate 12. Further, the external contact 26 cantake any suitable shape or combination of shapes in a plane orthogonalto the second major surface 16 of the substrate 12, e.g., square,tapered, domed, etc. In one or more embodiments, the contact 26 can takesubstantially the same shape as an external contact of one or moreadditional feedthroughs 20. In one or more embodiments, external contact26 can take a shape that is different from the shape of an externalcontact of one or more additional feedthroughs 20. Further, in one ormore embodiments, one or more external contacts 26 can include complexshapes such as grooves or channels formed in the contact to facilitateattachment of conductors or electronic devices to the contacts.

The external contact 26 can also include any suitable dimensions. In oneor more embodiments, the contact 26 can have any suitable thickness in adirection normal to the second major surface 16 of the substrate 12. Itis envisioned that for purposes of this disclosure, the dimension of thecontact thickness is limited only by the fabrication techniques utilizedto form the contact 26. In one or more exemplary embodiments, thisthickness can be at least 5 μm. In one or more embodiments, thethickness can be no greater than 10 mm, although greater thicknesses arealso contemplated. The thickness of the contact 26 can be the same as ordifferent from the thickness of an external contact of one or moreadditional feedthroughs 20. In one or more embodiments, the externalcontact 26 can be of sufficient size and thickness to enable laser,resistance, or other welding and joining techniques to be utilized toelectrically couple conductors and/or electronic devices to the externalcontact.

In one or more embodiments, the external contact 26 can be formed ordisposed over the via 22 on the second major surface 16 of the substrate12. For purposes of the present disclosure, the terms “form,” forming,”and “formed” will be used interchangeably with the terms “dispose,”“disposing,” and “disposed” respectively, such that the terms areconsidered to be equivalent. In other words, the external contact 26 isdisposed over the via 22 such that the contact covers the via and thevia is not visible in a plan view of the second major surface 16 of thesubstrate 12. In one or more embodiments, the external contact 26 (orany of the external contacts described herein) can be formed separatefrom the substrate 12 as a discrete member, or it could be patternedfrom a conductive sheet or foil as described herein (e.g., in referenceto FIGS. 8A-I), and disposed over the via 22 by attaching the formedcontact to the second major surface 16 of the substrate 12.

The external contact 26 is electrically connected to the conductivematerial 24 that is disposed in the via 22. In one or more embodiments,the external contact 26 is in direct contact with the conductivematerial 24 to electrically connect the contact to the conductivematerial. In one or more embodiments, one or more additional conductivelayers can be disposed between the external contact 26 and theconductive material 24 to electrically couple the external contact tothe conductive material.

In one or more embodiments, the external contact 26 is hermeticallysealed to the second major surface 16 of the substrate 12. Any suitabletechnique or combination of techniques can be utilized to hermeticallyseal the external contact 26 to the second major surface 16 of thesubstrate 12. For example, in one or more embodiments, the externalcontact 26 can be hermetically sealed to the second major surface 16 ofthe substrate 12 by a bond 50 (FIG. 3) that surrounds the via 22. Anysuitable technique or combination of techniques can be utilized to formthis bond 50. For example, in one or more embodiments, the bond 50 canbe formed using a laser to provide a laser bond. By surrounding the via22 with the bond 50 that hermetically seals the external contact 26 tothe second major surface 16 of the substrate 12, the via is alsoprotected from the external environment. The electrical connectionbetween the external contact 26 and the conductive material 24 disposedin the via 22 is, therefore, protected, and the integrity of thiselectrical pathway from the second major surface 16 of the substrate 12to the recessed surface 19 of the cavity 18 can be maintained. In one ormore embodiments, the external contact 26 can also be attached to thesecond major surface 16 of the substrate 12 using bonds in addition tobond 50. For example, in one or more embodiments, the external contact26 can be attached to the second major surface 16 by bond 50 and one ormore additional bonds between the external contact 26 and the secondmajor surface, e.g., point bonds.

FIG. 3 is a schematic plan view of a portion of the package 10 thatincludes feedthrough 20 of the assembly 10 of FIG. 1. The feedthrough 20is shown as viewed through the recessed surface 19 of the cavity 18. Thefeedthrough 20 includes the external contact 26, the via 22 includingthe conductive material 24 disposed in the via, and the bond 50. Thebond 50 hermetically seals the external contact 26 to the second majorsurface 16 of the substrate 12. The bond 50 can take any suitable shapeor combination of shapes such that it surrounds the via 22 as shown inFIG. 3. In one or more embodiments, the bond 50 can be a bond line 51.In one or more embodiments, the bond line 51 can form a closed shape ina plane parallel to the second major surface 16 of the substrate 12. Anysuitable closed shape or shapes can be formed by bond line 51, e.g.,elliptical, rectilinear, triangular, polygonal, etc.

In one or more embodiments, the bond 50 can be a bonded region thatsurrounds the via 22. The bonded region can take any suitable shape orcombination of shapes. In one or more embodiments, the bond 50 caninclude two or more shapes with one shape circumscribing the secondshape. For example, the bond 50 can include two or more concentricelliptical bond lines or rings. In such embodiments, the two or moreshapes may be isolated so that the shapes do not intersect or overlap.In one or more embodiments, the two or more shapes may intersect oroverlap along any suitable portion or portions of the shapes. In one ormore embodiments, the bond 50 can include two or more bond lines thattogether surround the via 22. For example, the bond 50 can include aseries of parallel lines that are intersected by two or more lines thatare non-parallel to the series of parallel lines.

In one or more embodiments, the bond 50 can include an interfacial layerbetween the external contact 26 and the second major surface 16 of thesubstrate 12. It should be understood that the thickness of theinterfacial layer is in part dependent on the intended function. Forexample, it may be desirable to form the interfacial layer as a stressbuffer, a barrier, or a spacer. Therefore, this interfacial layer canhave any suitable thickness in a direction normal to the second majorsurface 16. In one or more embodiments, the interfacial layer has athickness in a direction normal to the second major surface 16 of nogreater than 10 nm, 100 nm, 150 nm, 200 nm, 500 nm, or 10 μm.

As mentioned herein, any suitable technique or combination of techniquescan be utilized to form bond 48 between the inner surface 44 of thecover layer 40 and the first major surface 14 of the substrate 12, andto form bond 50 between the external contact 26 of the feedthrough 20and the second major surface 16 of the substrate, e.g., the techniquesdescribed in co-owned U.S. Patent Application No. 62/096,706 (MedtronicReference No. C00008775.USP1), entitled KINETICALLY LIMITED NANO-SCALEDIFFUSION BOND STRUCTURES AND METHODS. For example, FIG. 4 is aschematic cross-section view of a portion of the package 10 of FIG. 1.In one or more embodiments, electromagnetic radiation 70 (e.g., lightsuch as laser light) can be directed through the outer surface 46 of thecover layer 40 and directed (and/or focused) at an interface between theinner surface 44 of the cover layer and the first major surface 14 ofthe substrate 12 to form bond 48 (FIG. 2). Further, electromagneticradiation (e.g., electromagnetic radiation 70) can also be directedthrough the recessed surface 19 of substrate 12, and focused at a regionor an interface between the second major surface 16 of the substrate andthe external contact 26 to form bond 50 prior to connecting theelectronic device 30 to the internal contact 28 and attaching the coverlayer 40 to the first major surface 14 of the substrate 12. Theproperties of the electromagnetic radiation 70 can be selected based onthe material of the substrate 12 and the cover layer 40, and/orthickness and materials of the external contact 26, and controlled in apredetermined to form bonds 48, 50. For example, the electromagneticradiation 70 can include laser light having a suitable wavelength orrange of wavelengths and a predetermined pulse width or range of pulsewidths in one or more embodiments. The properties of the electromagneticradiation 70 are predicated on preferentially heating the interface ofthe substrate 12 and the external contact 26 to create an enhanced bond,such as bond 50, having a relatively greater strength than the bulkstrength of the substrate 12. Accordingly, a substrate that issubstantially transparent may be selected that is transmissive to lightof any desired wavelength. In one or more embodiments, the laser light70 can include light having a wavelength in a range of 10 nm to 30 μm.In one or more embodiments, the laser light can include a wavelength ofno greater than 2000 nm. For example, laser light 70 can include UVlight, visible light, IR light, and combinations thereof. The UV lightcan be provided by a UV laser that has any suitable wavelength or rangeof wavelengths and any suitable pulse width. In one or more embodimentswhere the thickness of the substrate 12 is approximately 100 to 500 μm,a laser can be utilized to provide light 70 having a wavelength in arange of 10 nm to 30 μm and a pulse width in a range of 1 ns to 100 ns.In one or more embodiments, the materials for the substrate 12, coverlayer 40, and the external contact 26, and the power level, pulse width,and wavelength of the light used may be selected such that the light maynot directly damage, ablate, warp, or cut the substrate, cover layer,and the contact, and such that the substrate, cover layer, and thecontact retain their bulk properties.

In general, light 70 can be provided by any suitable laser or lasersystem. For example, the laser may generate light having a relativelynarrow set of wavelengths (e.g., a single wavelength). In one or moreembodiments, the light 70 emitted by the laser may form a collimatedbeam that may not be focused at a particular point. In one or moreembodiments, the light 70 emitted by the laser may be directed (and/orfocused) at a focal point at an interface between the inner surface 44of the cover layer 40 and the first major surface 14 of the substrate 12to generate a laser bond 48. Further, in one or more embodiments, thelight emitted by the laser may be focused at a focal point at a regionor an interface between the external contact 26 and the second majorsurface 16 of the substrate 12 to generate the laser bond 50.

Although the laser may provide light 70 that has a narrow range ofwavelengths, in one or more embodiments, the laser may represent one ormore devices that emit electromagnetic radiation having a wider range ofwavelengths than a single typical laser. A wide variety of devices maybe used to emit electromagnetic radiation having a narrow or wide rangeof wavelengths. In one or more embodiments, the laser may include one ormore laser devices including diode and fiber lasers. Laser sources mayalso include, e.g., carbon dioxide lasers, TI sapphire lasers, argon ionlasers, Nd:YAG lasers, XeF lasers, HeNe lasers, Dye lasers, GaAs/AlGaAslasers, Alexandrite lasers, InGaAs lasers, InGaAsP lasers, Nd:glasslasers, Yb:YAG lasers, and Yb fiber lasers. The laser device may alsoinclude one of continuous wave, modulated, or pulsed modes. Accordingly,a wide variety of laser devices may be used in the bonding process. Inone or more embodiments, laser fluence of 1-2 J/cm2 may be used, with atop hat, Gaussian, or other suitable spatial energy profile.

In one or more embodiments, the feedthrough 20 can include an internalcontact 28 disposed on the recessed surface 19 of the recess 18. Theinternal contact 28 can include any suitable material or combinationmaterials, e.g., the same materials utilized for the external contact26. Further, the internal contact 28 can take any suitable shape orcombination of shapes and have any suitable thickness in a directionnormal to the recessed surface 19, e.g., the same shapes and thicknessesas described regarding the external contact 26.

The internal contact 28 is disposed over the via 22 on the recessedsurface 19. The contact 28 can be electrically connected to theconductive material 24 disposed in the via 22. In one or moreembodiments, the internal contact 28 is hermetically sealed to therecessed surface 19 using any suitable technique or combination oftechniques, e.g., by a bond (e.g., laser bond) that surrounds the via22. For example, FIG. 5 is a schematic plan view of a portion of thepackage 10 of FIG. 1. In FIG. 5, the internal contact 28 is shown asviewed from the recessed surface 19 of the substrate 12. As shown inFIG. 5, the internal contact 28 is attached to the recessed surface 19by bond 52, which is shown in dashed lines to indicate that the bond isnot visible in this view of package 10. Also shown in FIG. 5 is externalcontact 26 hermetically sealed to the outer surface of substrate 12 bybond 50.

In one or more embodiments, the internal contact 28 can be smaller thanthe external contact 26 in a dimension in the plane parallel to thesecond major surface 16 of the substrate 12. In one or more embodiments,the internal contact 28 can be the same dimension or dimensions asexternal contact 26. In one or more embodiments, the internal contact 28can be larger than the external contact 26 in a dimension in the planeparallel to the second major surface 16 of the substrate 12. Further,the internal contact 28 can take the same shape or combination of shapesas the external contact 26. In one or more embodiments, the internalcontact 28 can take a shape that is different from the shape of theexternal contact 26.

In one or more embodiments, the external contact 26 can be larger thanthe internal contact 28 such that the internal contact can first beattached to the recessed surface 19, e.g., by directing light throughthe substrate 12 from the second major surface 16 to a region orinterface between the internal contact and the recessed surface 19 toform bond 52. The external contact 26 can, in one or more embodiments,be hermetically sealed to the second major surface 16 of the substrate12 by directing light through the recessed surface to the region orinterface between the external contact and the second major surface toform bond 50 without the internal contact 28 being between the light andthe region where the bond 50 is formed. In one or more embodiments, theexternal contact 26 and the internal contact 28 can be relatively thesame size. In such embodiments, the external contact 26 and/or theinternal contact 28 can be attached to the substrate 12 in any suitableorder. For example, the external contract 26 can be attached to thesecond major surface 16 using light to form bond 50. The internalcontact 28 can then be attached to the recessed surface 19 by directinglight at an angle into the substrate 12 from the second major surface 16such that the external contact 26 does not block the light as it formsbond 52 to attach the internal contact 28 to the recessed surface 19. Inone or more embodiments, one or both of the external contact 26 and theinternal contact 28 can be bonded to the second major surface 16 and therecessed surface 19, respectively, to form a hermetic seal. In one ormore embodiments, only one of the bonds 48, 50 is formed as a hermeticseal.

As with bond 50, bond 52 can, in one or more embodiments, take anysuitable shape or combination of shapes and have any suitabledimensions, e.g., the shapes and dimensions described for bond 50. Forexample, as illustrated in FIG. 5, bond 52 can include a bond line 53.In one or more embodiments, bond 52 can include any suitable size andshaped region or regions that surround the via 22. Further, as is alsothe case with bond 50, bond 52 can include an interfacial layer betweenthe recessed surface 19 and the internal contact 28. This interfaciallayer can have any suitable thickness, e.g., the same thicknesses asthose described for bond 50. In one or more embodiments, the bond 52 canbe a laser bond.

As mentioned herein, any suitable conductors or contacts can be formedon one or both of the recessed surface 19 and the second major surface16 of the substrate 12. For example, as shown in FIG. 1, one or moreconductors 60 can be formed on the second major surface 16 of thesubstrate 12. Further, one or more conductors 62 can be disposed on therecessed surface 19. Any suitable number of conductors can be formed onone or both of the second major surface 16 and the recessed surface 19.Any suitable technique or combination of techniques can be utilized toform conductors 60, 62, e.g., chemical vapor deposition, plasma vapordeposition, physical vapor deposition, plating, etc., followed byphotolithography, chemical etching, etc. In one or more embodiments, aconductive material layer can be formed on one or both of the outersurface 16 and recessed surface 19, and the conductive material layercan be patterned to form conductors 60, 62. Further, the conductors 60,62 can include any suitable conductive material or combination ofconductive materials. In one or more embodiments, the conductor 60 canelectrically connect two or more external contacts 26 together, andconductor 62 can electrically connect two or more internal contacts 28together. In one or more embodiments, any of conductors 60, 62 can beconnected to one or more suitable electronic device(s). In one or moreembodiments, one or both of conductors 60, 62 can be formed to providean antenna for communication with one or more electronic deviceselectrically coupled to the package 10. Further, in one or moreembodiments, one or both of conductors 60, 62 can form an inductive coilthat can be utilized to provide inductive coupling to an externalinductive power supply. For example, if the package 10 is included in animplantable medical device, then conductor 60 can be used to form aninductive coil that can receive inductive energy from an externalinductive power supply to provide power to the implantable medicaldevice. In one or more embodiments, the inductive coil can be formed bypatterning one or more of the external contacts 26.

For example, FIG. 7 is a schematic plan view of another embodiment of asealed package 200. All of the design considerations and possibilitiesregarding the sealed package 10 of FIGS. 1-5 apply equally to the sealedpackage 200 of FIG. 7. Package 200 includes feedthroughs 220. Eachfeedthrough 220 includes an external contact 226 that can beelectrically connected to an internal contact, conductor, or device. Theassembly 200 also includes a conductor 260 that is electricallyconnected to external contact 227 of feedthrough 221 and externalcontact 224 of feedthrough 219. In one or more embodiments, theconductor 260 is adapted to form an antenna that can provide wirelesscommunication to one or more electronic devices disposed within thepackage 200, e.g., electronic device 30 of package 10 of FIG. 1. In oneor more embodiments, the conductor 260 can be adapted to form aninductive coil that can be inductively coupled with a power source toprovide power to one or more devices electrically coupled tofeedthroughs 219 and 221.

Returning to FIGS. 1-5, the conductors 60, 62 can take any suitableshape or combination of shapes and have any suitable dimensions.Further, one or more conductors 60, 62 can electrically connect thepackage 10 to ground, e.g., on an enclosure or housing of an implantablemedical device that includes the package.

Each of the conductors 60, 62 can be formed in separate steps. In one ormore embodiments, conductors on either or both of the second majorsurface 16 and the recessed surface 19 can be formed simultaneously withthe conductive material 24 disposed in the via and/or the external orinternal contacts 26, 28.

In one or more embodiments, one or more conductors 60, 62 can bedisposed such that the conductors are electrically connected to acontact, and the conductive material 24 disposed in the via 22. In suchembodiments, one or both of the bond 50 and the bond 52 would be formedbetween the contact, the conductor, and the substrate 12 such thatelectrical connection between the contact, the conductor, and theconductive material is maintained.

As mentioned herein, sealed package 10 can include one or moreelectronic devices 30 disposed within the enclosure 42. The electronicdevice 30 includes one or more device contacts 32 that can beelectrically connected to one or more feedthroughs 20. For example,device contact 32 can be electrically connected to the conductivematerial 24 disposed within the via 22 such that the electronic device30 is electrically connected to the external contact 26. The devicecontact 32 can be directly connected to the conductive material 24 inthe via 22. In one or more embodiments, one or more conductive layerscan be disposed between the device contact 32 and the conductivematerial 24 disposed within the via 22. For example, the device contact32 can be electrically connected to conductor 62, which can beelectrically connected to the conductive material 24 and via 22, therebyproviding an electrical pathway between the device 32 and the externalcontact 26. In one or more embodiments, the device contact 32 can beelectrically connected to the internal contact 28.

The electronic device 30 can be disposed in any suitable location withinthe enclosure 42. In one or more embodiments, the electronic device 30is disposed within the enclosure 42 such that the device is attached tothe recessed surface 19 of the cavity 18. In one or more embodiments,the electronic device 30 can be attached to the cover layer 40 andelectrically connected to one or more feedthroughs 20 when the coverlayer is attached to the substrate 12.

Any suitable electronic device 30 or devices can be disposed within theenclosure 42, e.g., one or more power sources, capacitors, transistors,integrated circuits, including controllers and multiplexers, andcombinations thereof. Any suitable number of electronic devices 30 canbe disposed within the enclosure 42. In one or more embodiments, theelectronic device 30 can be formed on the recessed surface 19 or on thecover layer 40. In one or more embodiments, the electronic device 30 canbe formed separately and then attached to the recessed surface 19,attached to the cover layer 40, or attached to both the recessed surfaceand the cover layer. Any suitable technique or combination of techniquescan be utilized to attach the electronic device 30 to one or both of therecessed surface 19 in the cover layer 40, e.g., a bond (e.g., bond 50of FIG. 4) can be formed between the electronic device and the recessedsurface 19.

The electronic device 30 can be electrically connected to one or moreadditional electronic devices disposed within the enclosure 42. In oneor more embodiments, the electronic device 30 can be electricallyconnected to the conductive material 24 disposed in one or more vias 22.Any suitable technique or combination of techniques can be utilized toelectrically connect the electronic device 30 to the conductive material24, e.g., one or more conductors 62 can be disposed on the recessedsurface 19, or the electronic device can be attached to one or moreinternal contacts 28. Further, in one or more embodiments, theelectronic device 30 can be electrically connected to other electroniccircuitry or devices disposed adjacent the substrate 12.

As mentioned herein, the various embodiments of sealed packagesdescribed herein can include any suitable number of feedthroughs. Thefeedthroughs can be disposed in any suitable arrangement. In one or moreembodiments, the feedthroughs can be disposed in a random configuration.In one or more embodiments, the feedthroughs can be disposed in anarray. For example, as illustrated in FIG. 2, the sealed package 20includes feedthroughs 20 disposed in the substrate 12. The feedthroughs20 can be disposed in an array 2. The array 2 can include any suitablenumber of feedthroughs 20. And the feedthrough array 2 can include anysuitable arrangement of feedthroughs 20.

The sealed packages described herein can include any suitable additionalelements or devices. For example, FIG. 6 is a schematic cross-sectionview of another embodiment of a sealed package 100. All of designconsiderations and possibilities regarding the package 10 of FIGS. 1-5apply equally to the package 100 of FIG. 6. The package 100 includes asubstrate 112 having a first major surface 114 and a second majorsurface 116, and a cavity 118 formed or disposed in the first majorsurface 114, where the cavity includes a recessed surface 119. Thepackage 100 also includes one or more feedthroughs 120. A cover layer140 can be disposed over the cavity 118 and attached to the first majorsurface 114 of the substrate 112 to form a sealed enclosure 142.

One difference between package 100 and package 10 is that severalelectronic devices 130 are disposed on or connected to the recessedsurface 119 of cavity 118. Any suitable electronic device can bedisposed on the recessed surface 119, e.g., capacitors, transistors,integrated circuits, including controllers and multiplexers, etc.Further, any suitable number of electronic devices 130 can be disposedon the recessed surface 119. Any suitable technique or combination oftechniques can be utilized to dispose the electronic devices 130 on therecessed surface 119. In one or more embodiments, the electronic devices130 can be formed on the recessed surface 119 of the substrate 112. Inone or more embodiments, each of the devices 130 can be formedseparately and then attached to the recessed surface 119. Any suitabletechnique or combination of techniques can be utilized to attach theelectronic devices 130 to the recessed surface 119, e.g., a bond (e.g.,bond 50 of FIG. 3) can be formed between the electronic device and therecessed surface.

Each of the electronic devices 130 can be electrically connected to oneor more additional electronic devices disposed on the recessed surface119 or within the enclosure 142. In one or more embodiments, theelectronic devices 130 can be electrically connected to conductivematerial 124 disposed in one or more vias 122. Any suitable technique orcombination of techniques can be utilized to electrically connect theelectronic devices 130 to the conductive material 124, e.g., one or moreconductors 162 can be disposed on the recessed surface 119, or one ormore the electronic devices 130 can be attached to an internal contact128. Further, in one or more embodiments, the electronic devices 130 canbe electrically connected to other electronic circuitry or devicesdisposed adjacent the substrate 112. In one or more embodiments, thefeedthrough 120 can provide a conductive pathway between the secondmajor surface 116 and one or more electronic devices 130.

Returning to FIGS. 1-5, the external contacts 26 can be disposed in anysuitable arrangement. In one or more embodiments, the external contacts26 can be disposed in a two-dimensional arrangement such as an array(e.g., array 2 of FIG. 2), or a three-dimensional arrangement. In otherwords, the sealed package 10 can include a substrate having athree-dimensional shape, e.g., spherical, cubic, conical, etc. In suchembodiments, one or more feedthroughs 20 can be disposed in anyarrangement such that the external contacts 26 can be provided in athree-dimensional configuration. See, e.g., co-owned U.S. Pat. No.7,822,482 to Gerber.

The various embodiments of sealed packages described herein (e.g.,sealed package 10 of FIGS. 1-5) can be formed using any suitabletechnique or combination of techniques. In general, the sealed packagesdescribed herein can be formed as single, discrete packages. In one ormore embodiments, two or more sealed packages can be formed on asubstrate or wafer and then singulated using any suitable technique orcombination of techniques.

FIGS. 8A-I are schematic views of one embodiment of a method 300 offorming a sealed package 310. All of the design considerations andpossibilities regarding the sealed package 10 of FIGS. 1-5 apply equallyto sealed package 310 of FIGS. 8A-I. In FIG. 8A, a substrate 312 isprovided. A first major surface 314 and a second major surface 316 ofthe substrate 312 can be prepared by polishing to remove surfacedeformities such as burrs, gouges, ridges, or other irregularities.Different techniques may be used to polish first major surface 314 andsecond major surface 316. For example, surfaces 314, 316 can bemechanically polished, chemically polished, or treated bychemical-mechanical polishing (CMP) techniques. Surfaces 314, 316 can bepolished until the surfaces exhibit comparatively low surface roughnessvalues that enhance direct bond formation. Although surfaces 314, 316may be polished to remove irregularities, the bonding process accordingto the present disclosure may not require the surfaces to be as smoothas surfaces used during typical wafer bonding techniques. Surfaces 314,316 may be cleaned to remove particles and contaminates. Cleaningsurfaces 314, 316 can include ultrasonic and/or megasonic cleaning.

In FIG. 8B, a cavity 318 can be formed in the first major surface 314 ofthe substrate 312. Any suitable technique or combination of techniquescan be utilized to form the cavity 318, e.g., etching, ablation,laser-assisted etching, and combinations thereof. The cavity 318includes a recessed surface 319. The recessed surface 319 can bepolished using any suitable technique or combination of techniques,e.g., the techniques described herein utilized to polish the first andsecond major surfaces 314, 316 of the substrate 312.

One or more vias 322 can be disposed in or formed between the firstmajor surface 314 and the second major surface 316 of the substrate 312as shown in FIG. 8C. Although illustrated as including two vias, thesealed package 310 can include any suitable number of vias. Further, anysuitable technique or combination of techniques can be utilized to formvia 322, e.g., drilling, etching, laser drilling, etc.

Although not shown, one or more conductors (e.g., conductor 60 ofFIG. 1) can optionally be formed on at least one of the first majorsurface 314 and the second major surface 316. Any suitable technique orcombination of techniques can be utilized to form such conductors. Forexample, in one or more embodiments, a conductive material layer (notshown) can be formed on the second major surface 316. The conductivematerial layer can be formed, e.g., using plasma vapor deposition,chemical vapor deposition, physical vapor deposition, etc. One or moreportions of the conductive material layer can then be removed to formthe conductors using any suitable technique or combination oftechniques, e.g., photolithography, etc. Any suitable number ofconductors can be formed on the second major surface 316 of substrate312.

One or more external contacts 326 can be formed on the second majorsurface 316 of substrate 312 using any suitable technique or combinationof techniques. For example, as illustrated in FIG. 8D, a conductivematerial layer 325 can be disposed on and/or coupled to the second majorsurface 316 over the conductors (if present) and the vias 322. In one ormore embodiments, the conductive material layer 325 can be attached tothe second major surface 316 of the substrate 312 using any suitabletechnique or combination of techniques, e.g., forming a bond thathermetically seals the conductive layer to the second major surface. Theconductive material layer 325 can be attached to the second majorsurface 316.

Any suitable technique or combination of techniques can be utilized toattach the conductive layer 325 to the second major surface 316, e.g.,the techniques described in U.S. Patent Application No. 62/096,706(Medtronic Reference No. C00008775.USP1), entitled KINETICALLY LIMITEDNANO-SCALE DIFFUSION BOND STRUCTURES AND METHODS. For example,electromagnetic radiation can be directed through substrate 312 from thefirst major surface 314 to an interface between the conductive layer325, the conductors (if present), and the second major surface 316. Theelectromagnetic radiation can form a bond (e.g., bond 50 of FIG. 5) thathermetically seals the conductive layer 325 to the substrate 312 in anysuitable pattern or shape. The bond can be a laser bond. In one or moreembodiments, a bond surrounds the via 322.

As illustrated in FIG. 8E, one or more portions of the conductivematerial layer 325 can be removed to form one or more external contacts326 on the second major surface 316 of the substrate 312. Any suitabletechnique or combination of techniques can be utilized to form theexternal contacts 326, e.g., photolithography, etching, laser ablation,etc. In or more embodiments, a mask or masks can be formed on the secondmajor surface 316 of the substrate 312, and the conductive materiallayer 325 can be formed over the mask. Portions of the conductivematerial layer 325 that are formed on the mask itself can be removedusing any suitable technique or combination of techniques, includingphotolithography, etching, laser ablation etc., to form externalcontacts 326. In addition, one or more portions of the conductivematerial layer 325 can also be removed or patterned to create otherelectrical components, such as an antenna.

The bond formed between the external contact 326 and the second majorsurface 316 remains intact such that it hermetically seals the contactto the second major surface. In other words, portions of the conductivelayer 325 that are hermetically sealed to the second major surface 316are not removed when the external electrodes 326 are patterned. Similartechniques can be utilized to form internal contacts on the recessedsurface 319 of the cavity 318. The external contact 326 can beelectrically connected to the conductors (if present).

Conductive material 324 can be formed in the via 322 as shown in FIG.8F. Any suitable technique or combination of techniques can be utilizedto form or dispose the conductive material 324 in the vias 322, e.g.,plasma vapor deposition, chemical vapor deposition, physical vapordeposition (e.g., sputtering), plating, conductive composite pastes,etc. Further, the conductive material 324 may substantially fill thevias 322. In one or more embodiments, conductive material 324 can beformed on one or more sidewalls of the vias 322 to form or dispose oneor more conductors within the via.

In one or more embodiments, the recessed surface 319 of the recess 318can be polished to remove any excess conductive material 324. Anysuitable technique or combination techniques can be utilized to polishthe recessed surface 319.

In one or more embodiments, one or more conductors that have beendisposed on one or both of the recessed surface 319 and the second majorsurface 316 can be electrically connected to the conductive material 324in the vias 322. In such embodiments, such conductors can beelectrically connected using any suitable technique, e.g., theelectrical conductors are in physical contact with the conductivematerial. In one or more embodiments, the conductors and the conductivematerial 324 can include the same material or combination of materials.Further, in one or more embodiments, the conductors and the conductivematerial 324 can be formed or disposed simultaneously or sequentially.

In FIG. 8G, one or more internal contacts 328 can be formed or disposedon the recessed surface 319 of the cavity 318 to provide feedthrough520. In one or more embodiments, one or more of the internal contacts328 can be disposed over the via 322 such that the internal contacts 328are electrically connected to the conductive material 324 disposed inthe vias. Any suitable technique or combination of techniques can beutilized to form internal contacts 328, e.g., the same techniquesdescribed herein regarding the external contacts 326. In one or moreembodiments, the external contact 326, the via 322, the conductivematerial 324 disposed in the via, and the internal contact 328 provide afeedthrough 320 that can provide an electrical pathway between thecavity 318 and the second major surface 316 of the substrate 312. In oneor more embodiments, the feedthroughs 320 can be provided by theexternal contact 326, the via 322 and the conductive material 324disposed within the via and does not include an internal contact 328 asis further described herein.

One or more electronic devices 330 can be disposed at least partiallywithin the cavity 318 as shown in FIG. 8H. Electronic device 330 caninclude any suitable electronic device or devices. In one or moreembodiments, the electronic device 330 can include a power source thatcan be at least partially disposed within the cavity 318 prior toattaching a cover layer 340 to the first major surface 314 of thesubstrate 312. The power source can be electrically connected to one ormore electronic devices disposed within the cavity 318.

The electronic device 330 can be disposed at least partially within thecavity 318 such that a device contact 332 of the electronic device iselectrically connected to the conductive material 324 in the via 322.The electronic device 330 can include any suitable number of devicecontacts 332. The electronic device 330 can, therefore, be electricallyconnected to the external contact 326 when the device contact 332 iselectrically connected to the conductive material 324 disposed withinthe via 322. In other words, an electrical pathway can be providedbetween the electronic device 330 and the second major surface 316 ofthe substrate 312 by electrically connecting the device to thefeedthrough 320. In one or more embodiments, the device contact 332 canbe electrically connected directly to the conductive material number 324without an intervening internal contact 328 being present. Optionally,an insulative material (not shown) can be disposed within the cavity 318such that the insulative material at least partially surrounds theelectronic device 330. The insulative material, therefore, can bedisposed within a sealed enclosure 342 that is formed by the cover layer340 being disposed on the first major surface 314 of the substrate 312as is further described herein. Any suitable insulative material orcombination of materials can be disposed within the cavity 318 such thatthe insulative material at least partially surrounds the electronicdevice 330.

As shown in FIG. 8I, the cover layer 340 can be disposed over the cavity318. The cover layer 340 can be attached to the first major surface 314of the substrate 312 to form the sealed enclosure 342. In one or moreembodiments, the electronic device 330 can be disposed within the sealedenclosure 342. Further, in one or more embodiments, the enclosure 342can be a hermetically-sealed enclosure.

Any suitable technique or combination of techniques can be utilized toattach the cover layer 340 to the first major surface 314 of thesubstrate 312. For example, in one or more embodiments, the cover layer340 can be attached to the first major surface 314 of the substrate 312by laser bonding the cover layer to the first major surface as isfurther described herein. In one or more embodiments, laser bonding thecover layer 340 can include forming a bond line in a region or at aninterface between the first major surface 314 of the substrate 312 andthe cover layer such that the bond line surrounds the cavity 318.

FIGS. 13A-H are schematic cross-section views of another embodiment of amethod 700 for forming a sealed package 710. All of the designconsiderations and possibilities regarding the sealed package 10 ofFIGS. 1-5 and the sealed package 310 of FIGS. 8A-I apply equally to thesealed package 710 of FIGS. 13A-H. In method 700, a substrate 712 isprovided. A first major surface 714 and a second major surface 716 ofthe substrate 712 can be prepared by polishing to remove surfacedeformities such as burrs, gouges, ridges, or other irregularities.Different techniques may be used to polish the first major surface 714and the second major surface 716. For example, surfaces 714, 716 can bemechanically polished, chemically polished, or treated bychemical-mechanical polishing (CMP) techniques. Surfaces 714, 716 can bepolished until the surfaces exhibit comparatively low surface roughnessvalues that enhance direct bond formation. Although surfaces 714, 716may be polished to remove irregularities, the bonding process accordingto the present disclosure may not require the surfaces to be as smoothas surfaces used during typical wafer bonding techniques. Surfaces 714,716 may be cleaned to remove particles and contaminates. Cleaningsurfaces 714, 716 can include ultrasonic and/or megasonic cleaning.

In FIG. 13B, a cavity 718 can be formed in the first major surface 714of the substrate 712. Any suitable technique or combination oftechniques can be utilized to form the cavity 718, e.g., etching,ablation, laser-assisted etching, and combinations thereof. The cavity718 includes a recessed surface 719. The recessed surface 719 can bepolished using any suitable technique or combination of techniques,e.g., the techniques described herein utilized to polish the first andsecond major surfaces 714, 716 of the substrate 712.

In FIG. 13C, a conductive material layer 725 including a conductivesheet or foil as described in reference to FIGS. 8A-I can be disposed onthe second major surface 716 of the substrate 712. The conductivematerial layer 725 can be attached to the second major surface 716 usingany suitable technique or combination of techniques, e.g., forming abond that hermetically seals the conductive layer to the second majorsurface. For example, electromagnetic radiation can be directed throughone or both of the first major surface 714 of the substrate 712 and therecessed surface 719 and directed at an interface of the conductivematerial layer 725 and the second major surface 716 to form one or morebonds between the conductive material layer and the second majorsurface.

One or more portions of the conductive material layer 725 can be removedto form one or more external contacts 726 on the second major surface716 as illustrated in FIG. 13D. Any suitable technique or combination oftechniques can be utilized to form the external contacts 726, including,for example, photolithography, etching, laser ablation, etc. In one ormore embodiments, a mask or masks can be formed on the second majorsurface 716, and the conductive material layer 725 can be formed overthe mask. Portions of the conductive material layer 725 that are formedon the mask itself can be removed using any suitable technique orcombination of techniques to form external contacts 726. In one or moreembodiments, the bond formed when the conductive material layer 726 wasattached to the substrate 712 remains between the external contact 726and the second major surface 716 of the substrate 712 such that thecontact is hermetically sealed to the outer surface. Any suitabletechnique or combination of techniques can be utilized to form externalcontacts 726.

As shown in FIG. 13E, one or more vias 722 can be formed through thesubstrate 712. Each via 722 can be formed such that it is within aclosed shape or region defined by the bond such that the bond surroundsthe via. Because the via 722 is within the shapes or regions formed bythe bonds, the via 722 can be protected from the external environment.In one or more embodiments, an etch stop layer can be formed between theconductive material layer 725 and the second major surface 716 of thesubstrate 712 to prevent the formation of the via 722 from removingportions of the external contact 726.

Although not shown, one or more conductors can optionally be formed onthe external contact 726 and/or on the second major surface 716 of thesubstrate 712. In one or more embodiments, one or more conductors can beelectrically coupled to the external contact 726. Any suitable techniqueor combination of techniques can be utilized to form such conductors. Inone or more embodiments, the conductors can be provided by forming aconductive material layer over the external contact 726 and the secondmajor surface 716. This conductive material layer can then be patternedto form conductors in any desirable configuration.

As shown in FIG. 13F, conductive material 724 can be disposed in the via722 to provide a conductive pathway from the external contact 726 toconductors, contacts, electronic devices, etc. disposed on thefirst-major-surface 714 side of the substrate 712, thereby providingfeedthrough 720. Any suitable technique or combination of techniques canbe utilized to form the conductive material 724 in the via 722. Asmentioned herein, the via 722 can be substantially filled with theconductive material 724. In one or more embodiments, the conductivematerial 724 can be disposed on a portion or portions of one or moresidewalls of the vias as shown in FIG. 13F. Further, one or moreconductors 750 can optionally be formed on the first major surface 714of the substrate 712 either simultaneously with forming conductivematerial 724 in the vias 722 or sequentially. In one or moreembodiments, the same material utilized for the conductive material 725can also be utilized to form conductors 750. Conductors 750 can beformed using any suitable technique or combination of techniques. Theoptional conductors 750 described herein can be provided to, forexample, electrically couple an electronic device or contact disposed onthe first major surface 716 to the conductive material 724 in the via722.

One or more electronic devices 730 can be disposed at least partiallywithin the cavity 718 as shown in FIG. 13G. Electronic device 730 caninclude any suitable electronic device or devices. In one or moreembodiments, the electronic device 730 can include a power source thatcan be at least partially disposed within the cavity 718 prior toattaching a cover layer 740 to the first major surface 714 of thesubstrate 712. The power source can be electrically connected to one ormore electronic devices disposed within the cavity 718.

The electronic device 730 can be disposed at least partially within thecavity 718 such that a device contact 732 of the electronic device iselectrically connected to the conductive material 724 in the via 722either directly or through electrical connection to conductor 750. Theelectronic device 730 can include any suitable number of device contacts732. The electronic device 730 can, therefore, be electrically connectedto the external contact 726 when the device contact 732 is electricallyconnected to the conductive material 724 disposed within the via 722. Inother words, an electrical pathway can be provided between theelectronic device 730 and the second major surface 716 of the substrate712 by electrically connecting the device to the feedthrough 720. In oneor more embodiments, the device contact 732 can be electricallyconnected directly to the conductive material number 724 without anintervening internal contact or conductor 750 being present.

As shown in FIG. 13H, the cover layer 740 can be disposed over thecavity 718. The cover layer 740 can be attached to the first majorsurface 714 of the substrate 712 to form a sealed enclosure 742. In oneor more embodiments, the electronic device 730 can be disposed withinthe sealed enclosure 742. Further, in one or more embodiments, theenclosure 742 can be a hermetically-sealed enclosure.

Any suitable technique or combination of techniques can be utilized toattach the cover layer 740 to the first major surface 714 of thesubstrate 712. For example, in one or more embodiments, the cover layer740 can be attached to the first major surface 714 of the substrate 712by laser bonding the cover layer to the first major surface as isfurther described herein. In one or more embodiments, laser bonding thecover layer 740 can include forming a bond line in a region or at aninterface between the first major surface 714 of the substrate 712 andthe cover layer such that the bond line surrounds the cavity 718.

Optionally, an insulative material (not shown) can be disposed withinthe cavity 718 such that the insulative material at least partiallysurrounds the electronic device 730. The insulative material, therefore,can be disposed within a sealed enclosure 742 that is formed by thecover layer 740 being disposed on the first major surface 714 of thesubstrate 712 as is further described herein. Any suitable insulativematerial or combination of materials can be disposed within the cavity718 such that the insulative material at least partially surrounds theelectronic device 730.

The various embodiments of sealed packages described herein can beutilized with any device or system that requires sealed conductivepathways between an exterior of the device to one or more electronicdevices or components disposed within an interior of the package. Forexample, one or more embodiments of sealed packages described herein canbe utilized with an implantable medical device or system. Nearly anyimplantable medical device or system employing leads may be used withthe various embodiments of sealed packages described herein.Representative examples of such implantable medical devices includehearing implants, e.g., cochlear implants; sensing or monitoringdevices; signal generators such as cardiac pacemakers or defibrillators,neurostimulators (such as spinal cord stimulators, brain or deep brainstimulators, peripheral nerve stimulators, vagal nerve stimulators,occipital nerve stimulators, subcutaneous stimulators, etc.), gastricstimulators; or the like.

For example, FIG. 9 is a schematic side view of one embodiment of animplantable medical device system 400. The system 400 includes animplantable medical device (IMD) 402, a lead 490, and a lead extension482. In one or more embodiments, the system 400 can also include asealed package (e.g., sealed package 10 of FIGS. 1-5).

The IMD 402 includes a connector header 404 adapted to receive aproximal portion 481 of the lead extension 482. A proximal portion 481of lead extension 482 includes one or more electrical contacts 484 thatare electrically coupled to internal contacts (not shown) at distalconnector 486 of the lead extension. The connector header 404 of the IMD402 includes internal contacts (not shown) and is adapted to receive theproximal portion 481 of the lead extension 482 such that the internalcontacts of the connector header may be electrically coupled to thecontacts 484 of the lead extension when the lead extension is insertedinto the header.

The system 400 depicted in FIG. 9 further includes lead 490. Thedepicted lead 490 has a proximal portion 491 that includes contacts 492and a distal portion 493 that includes electrodes 494. Each of theelectrodes 494 can be electrically coupled to a discrete contact 492.The distal connector 486 of the lead extension 482 is adapted to receivethe proximal portion 491 of the lead 490 such that the contacts 492 ofthe lead may be electrically coupled to the internal contacts of theconnector of the extension. Accordingly, a signal generated by the IMD402 can be transmitted to tissue of a patient by an electrode 494 oflead 490 when the lead is connected to the extension 482 and theextension is connected to the IMD. Alternatively or in addition, asignal received by electrode 494 of lead 490 from a patient may betransmitted to a contact of the IMD 402 when the lead is connected tothe extension 482 and the extension is connected to the IMD.

It will be understood that lead 490 can be connected to IMD 402 withoutuse of an extension 482. Any number of leads 490 or extensions 482 canbe connected to device 402. While lead 490 is depicted as having fourelectrodes 494, it will be understood that the lead can include anynumber of electrodes, e.g. 1, 2, 3, 4, 5, 6, 7, 8, 16, 32, or 64electrodes. Corresponding changes in the number of contacts 492 in lead490, contacts 484 and internal contacts in connector 486 of leadextension, or internal contacts in header 404 of device 402 may berequired or desired.

As used hereinafter, “lead” will refer to both “leads” and “leadextensions” unless the content and context clearly dictates otherwise.

FIG. 10 is a schematic cross-section view of the IMD 402 of FIG. 9. TheIMD 402 further includes a sealed package 410 that includes one or moreelectronic devices 430 disposed within a sealed enclosure 442, and theconnector header 404 disposed on or attached to the sealed package. Thesealed package 410 can include any sealed package described herein,e.g., sealed package 10 of FIGS. 1-5. All of the design considerationsand possibilities regarding the sealed package 10 of FIGS. 1-5 applyequally to the sealed package 410 of FIG. 10. A lead receptacle 405 isformed in a housing 407 of the header 404. The receptacle 405 is adaptedto receive and electrically connect to contacts 484 of the leadextension 482 (or contacts 492 of the lead 490).

The receptacle 405 has internal contacts 409 positioned to align withand electrically couple with contacts 484 of the lead extension 482and/or contacts 492 of the lead 490 when the lead extension or lead isproperly inserted into the receptacle. The pitch of the internalcontacts 409 of FIG. 10 is adapted to allow electrical connectionbetween the contacts 484 of the lead extension 482 or contacts 492 oflead 490.

The electronic device 430 disposed within the sealed package 410 can beadapted to send electrical signals to a tissue of a patient, or receivesignals from a tissue of a patient, through leads operably coupled tothe electronics of the IMD 402. As used herein, the term “transmittedelectrical signals” is used to refer to both the signals sent by theelectronic device 430 to tissue of the patient or received by theelectronics from the tissue of the patient. In one or more embodiments,the electronic device 430 can be electrically connected to internalcontacts 409 of lead receptacle 405 via feedthroughs 420 of the sealedpackage 410. For example, in one or more embodiments, device contact 432of the electronic device 430 can be electrically connected to conductivematerial 424 disposed within via 422. The device contact 432 can,therefore, be electrically connected to external contact 426 offeedthrough 420 through the conductive material 424 disposed in the via422. The external contact 426 can in turn be electrically connected tothe internal contact 409 of lead receptacle 405 by conductor 408. Anelectrical pathway is, therefore, formed between the internal contact409 of lead receptacle 405 and electronic device 430.

In one or more embodiments, each conductor 408 can electrically couplean internal contact 409 of the lead receptacle 405 to a discrete channelof the electronic device 430. As used herein, a “channel” of theelectronics is a discrete electronic pathway through which signals maybe transmitted independently of another channel. The feedthroughs 420can be electrically connected with internal contacts 409 via welding,soldering, brazing, coupling via conductive wires, or the like. Eachchannel of the electronics 406 can be independently connected with adiscrete internal contact 409 of a receptacle, which can be coupled witha discrete contact 484 of the lead extension 482 or contact 492 of thelead 490, which can be coupled with a discrete electrode 494 of thelead. Accordingly, each channel of the electronics 406 can be operablycoupled to a given electrode 494 of a lead.

The various embodiments of hermetically-sealed packages described hereincan be utilized with any system or device. For example, FIG. 11 is aschematic cross-section view of one embodiment of a lead 500. The lead500 can be any suitable lead known in the art (e.g., lead 490 ofimplantable medical device 400 of FIGS. 9-10). All of the designconsiderations and possibilities regarding lead 490 (and lead extension482) of FIG. 9 apply equally to lead 500 of FIG. 10. Further, the lead500 can be utilized with any suitable external medical device orimplantable medical device (e.g., implantable medical device 402 ofsystem 400 of FIGS. 9-10). The lead 500 includes a lead body 502 thathas a distal portion 504 and a proximal portion 506 that includes one ormore contacts 508.

One difference between lead 500 and lead 490 is that lead 500 includesthe sealed package 10 of FIGS. 1-5 disposed on or in the distal portion504 of the lead body 502. Although the lead 500 is illustrated asincluding the package 10 of FIGS. 1-5, any sealed package can beutilized with the lead. In the embodiment illustrated in FIG. 11, thepackage 10 is coupled to a portion, e.g., the distal portion 504, of thelead body 502. The lead 500 optionally includes one or more outputconductors 512 that are connected to the package 10. The one or moreoutput conductors 512 can electrically connect the package 10 toelectrodes 580 a-d that are disposed on the lead 500. In one or moreembodiments, the electronic device 30 can include a multiplexer that canbe used for selective coupling of one or more of the electrodes 520 a-dto one or more conductors or filers 509 as will be described in greaterdetail herein.

In one or more embodiments, the discrete contact 508 of the lead 500 canbe electrically connected to the package 10 using any suitable techniqueor combination of techniques. In one or more embodiments, the discretecontact 508 of the lead 500 can be electrically connected to the package10 through one or more conductors or filers 509 that are disposed on orwithin the lead body 502. The discrete contact 508 can be electricallyconnected to one or more of the feedthroughs 20 of the package 10 eitherdirectly or through the electronic device 30. For example, in one ormore embodiments, the electronic device 30 can be a multiplexer that iselectrically connected to one or more discrete contacts 508 of the leadand a feedthrough 21. Any suitable multiplexer can be utilized with thelead 500, e.g., the multiplexers described in co-owned U.S. Pat. No.7,822,482 to Gerber. The electronic device 30 can be electricallyconnected to one or more discrete contacts 508 by a conductor or filer509 that is disposed on or within the lead body 502 and is electricallyconnected to feedthrough 21 as shown in FIG. 11. The feedthrough 21 canbe any suitable feedthrough described herein, e.g., feedthrough 20 ofpackage 10. Further, any suitable technique or combination of techniquescan be utilized to form the feedthrough 21 through one or both of thesubstrate 12 and the cover layer 40, e.g., the same techniques describedfor forming feedthrough 20 of package 10.

The feedthrough 21 can provide a sealed electrical pathway from thediscrete contact 508 to the electronic device 30. Although onefeedthrough 21 is illustrated as being formed through substrate 12 ofpackage 10, any suitable number of feedthroughs can be formed throughone or both of the substrate and the cover layer 40 to electricallyconnect any suitable number of contacts 508 to the electronic device 30.

The lead body 502 can include one or more conductors 509 that provideone or more inputs to the multiplexer 30. And the package 10 can includeone or more conductors that provide one or more outputs from theelectronic device 30 to the one or more feedthroughs 20. In one or moreembodiments, outputs of the electronic device 30 can be directlyconnected to one or more internal contacts 28 of the package 10. In oneor more embodiments, the number of outputs of the electronic device 30corresponds to the number of external contacts 26, as there is oneoutput for each external contact. Further, in one or more embodiments,the number of outputs is greater than the number of input conductors509. The use of electronic device 30 within lead body 502 can reduce thenumber of input conductors 509 that extend along the entire length ofthe lead body.

With the electronic device 30 adjacent the distal portion 504 of thelead 500, the number of input conductors 509 that extend alongsubstantially the entire length of lead body 502 can be reduced. Forexample, the input conductors 509 may include a chip power conductor, achip ground conductor, a serial addressing conductor, a stimulationpower conductor, and a stimulation return conductor return. The chippower and chip ground conductors can deliver operating power to theelectronic device 30. The stimulation power and return conductorsdeliver stimulation pulses for application across a set of electrodes(e.g., electrodes 520 a-d) in distal portion 504 of the lead 500, which,in the illustrated embodiment, are the external contacts 26 of thepackage 10. The serial addressing conductor carries a serial codewordthat identifies a combination of external contacts 26 for application ofstimulation pulses. Each of the electrodes 520 a-d can be electricallycoupled to the external contacts 26 directly or through one or moreoutput conductors 512 as shown in FIG. 11. In response to the codeword,the electronic device 30 configures a switch matrix to direct thestimulation pulses across the specified combination of two or moreexternal contacts 26. The codeword may be transmitted by pulse widthmodulation or other serial bus schemes, and may specify the externalcontacts 26 to be included in a contact combination, as well as thepolarities of the contacts. In response to the address codeword,electronic device 30 applies the stimulation current across thespecified set of external contacts 26.

In one or more embodiments, one or more therapeutic electrodes can beelectrically connected to one or more external contacts 26 of thepackage 10. In one or more embodiments, one or more of the externalcontacts 26 can be connected to electrodes through conductors to provideelectrical stimulation therapy to a patient or sense physiologicalsignals, such as cardiac signs, from a patient.

Various embodiments of sealed packages described herein can include oneor more feedthroughs that provide an electrical pathway from an externalsurface of the package to an enclosure within the package. In one ormore embodiments, a sealed package does not require one or morefeedthroughs but instead is contained completely within an enclosure ofthe package. For example, FIG. 12 is a schematic cross-section view ofone embodiment of a sealed package 600. All of the design considerationsand possibilities regarding the sealed package 10 of FIGS. 1-5 applyequally to the sealed package 600 of FIG. 12. Sealed package 600includes a substrate 612 that includes a first major surface 614 and asecond major surface 616. A cavity 618 can be disposed in the firstmajor surface 614. The cavity can include a recessed surface 619. Thepackage 600 also includes one or more internal contacts 628 disposed onthe recessed surface 619 of the cavity 618. Electronic device 630includes one or more device contacts 632. In one or more embodiments,one or more of the device contacts 632 can be electrically connected toone or more of the internal contacts 628 using any suitable technique orcombination of techniques. The packaged 600 can also include a coverlayer 640 disposed over the cavity 618 and attached to the first majorsurface 614 of the substrate 612 to form a sealed enclosure 642. In oneor more embodiments, the electronic device 630 can be disposed withinthe sealed enclosure 642. Further, in one or more embodiments, thesealed enclosure 642 can be a hermetically-sealed enclosure. The package600 can also include one or more conductors 660 disposed on one or bothof the recessed surface 619 and an inner surface 644 of the cover layer640. The one or more conductors 660 can electrically connect one or moreof the internal contacts 628 together to form any suitable circuit orcircuitry disposed within the sealed cavity 642. Although not shown, thesealed enclosure 642 can be at least partially filled with an insulativematerial to help protect the electronic device 630 from exposure toexternal environmental factors and to maintain the electronic deviceelectrical connection with the internal contacts 628.

All references and publications cited herein are expressly incorporatedherein by reference in their entirety into this disclosure, except tothe extent they may directly contradict this disclosure. Illustrativeembodiments of this disclosure are discussed and reference has been madeto possible variations within the scope of this disclosure. These andother variations and modifications in the disclosure will be apparent tothose skilled in the art without departing from the scope of thedisclosure, and it should be understood that this disclosure is notlimited to the illustrative embodiments set forth herein. Accordingly,the disclosure is to be limited only by the claims provided below.

What is claimed is:
 1. A method of forming a hermetically-sealedpackage, comprising: disposing an electronic device at least partiallywithin a cavity of a non-conductive substrate, wherein thenon-conductive substrate comprises a first major surface and a secondmajor surface, and further wherein the cavity is disposed in the firstmajor surface of the non-conductive substrate; disposing a cover layerover the cavity; and attaching the cover layer to the first majorsurface of the non-conductive substrate to form a hermetically-sealedenclosure, wherein the electronic device is disposed within thehermetically-sealed enclosure, and further wherein attaching the coverlayer comprises laser bonding the cover layer to the first major surfaceof the non-conductive substrate by forming a bond line at an interfacebetween the first major surface of the substrate and the cover layer. 2.The method of claim 1, further comprising: disposing a power source atleast partially within the cavity of the non-conductive substrate priorto attaching the cover layer to the first major surface of thenon-conductive substrate; and electrically connecting the power sourceto the electronic device.
 3. The method of claim 1, further comprisingforming a via between a recessed surface of the cavity and the secondmajor surface of the non-conductive substrate.
 4. The method of claim 3,further comprising forming an external contact over the via on thesecond major surface of the non-conductive substrate.
 5. The method ofclaim 4, wherein forming the external contact comprises: disposing aconductive layer on the second major surface over the via; and removinga portion of the conductive layer to form the external contact over thevia.
 6. The method of claim 5, further comprising attaching theconductive layer to the second major surface of the non-conductivesubstrate prior to removing the portion of the conductive layer.
 7. Themethod of claim 6, wherein attaching the conductive layer to the secondmajor surface of the non-conductive substrate comprises directingelectromagnetic radiation through one or both of the first major surfaceof the non-conductive substrate and the recessed surface at an interfaceof the conductive layer and the second major surface of thenon-conductive substrate to form one or more bonds between theconductive layer and the second major surface.
 8. The method of claim 4,further comprising electrically connecting the external contact to theelectronic device.
 9. The method of claim 4, wherein the externalcontact is adapted to provide an electrical signal to tissue of apatient.
 10. The method of claim 1, further comprising forming anantenna on at least one of the first major surface or second majorsurface of the non-conductive substrate.
 11. The method of claim 10,further comprising electrically connecting the antenna to the electronicdevice.
 12. The method of claim 1, wherein disposing the electronicdevice comprises disposing the electronic device entirely within thecavity of the non-conductive substrate.
 13. The method of claim 1,further comprising forming the cavity in the first major surface of thenon-conductive substrate prior to disposing the electronic device atleast partially within the cavity.
 14. The method of claim 13, whereinforming the cavity comprises etching the first major surface of thenon-conductive substrate.
 15. The method of claim 13, wherein formingthe cavity comprises ablating the first major surface of thenon-conductive substrate.
 16. The method of claim 13, further comprisingpolishing at least one of the first major surface or second majorsurface of the non-conductive substrate prior to forming the cavity inthe first major surface of the non-conductive substrate.
 17. The methodof claim 1, further comprising forming an internal contact on a recessedsurface of the cavity.
 18. The method of claim 17, further comprisingelectrically connecting the electronic device to the internal contact.19. The method of claim 1, further comprising disposing an insulativematerial within the hermetically-sealed enclosure.
 20. The method ofclaim 1, wherein the laser bond line surrounds the cavity of thenon-conductive substrate.